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Sterically Hindered Cyclic Diynes − Syntheses and Structures
Author(s) -
Schaefer Carsten,
Gleiter Rolf,
Rominger Frank
Publication year - 2003
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.200300151
Subject(s) - chemistry , steric effects , ring (chemistry) , alkyne , yield (engineering) , solid state , stereochemistry , cyclohexane conformation , crystallography , molecule , organic chemistry , hydrogen bond , catalysis , materials science , metallurgy
The synthesis of three 14‐membered ring systems 8a − 8c with the 1,3,8,10‐tetraoxa‐2,9‐disilacyclotetradeca‐5,12‐diyne skeleton is described. In all three ring systems the α‐positions are substituted with gem ‐dimethyl and/or gem ‐diphenyl groups. Structural investigations on 8a and 8c reveal a chair like conformation of the central ring with parallel alkyne units. For 8b the voluminous phenyl groups cause a twist‐chair and a twist‐boat conformation. Columnar structures were encountered for 8a in the solid state. Reactions with octacarbonyldicobalt yield for 8a mono‐ and biscomplexation ( 12 , 13 ). For 8b only the mono complexation product 14 was isolated. For 8c the bis(hexacarbonyldicobalt) complex 15 was obtained. X‐ray investigations revealed columnar structures in the solid state for 12 , 13 , and 15 . (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)